Option-type paper feeding device

ABSTRACT

The invention provides an option-type paper feeding device that can contribute to enhancing printing operation efficiency while taking advantage of variable printing speed in a printing apparatus. A high-volume paper feeding device includes: a paper stacking section; a paper feeding mechanism; and an intermediate transport section connected to a paper feeding section of a printing apparatus such as a stencil printing apparatus. The intermediate transport section includes: a first paper transport means; and a second paper transport means provided downstream of the first paper transport means, and an inkjet printing section is provided above the first paper transport means. The transport speed of the first paper transport means is fixed to a speed suitable for printing by the inkjet printing section, while the transport speed of the second paper transport means is variable. The transport speed of the second paper transport means is adjusted by control means (not shown in drawings) in accordance with the printing speed of a printing apparatus connected to the high-volume paper feeding device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a paper feeding device for separating and feeding, sheet by sheet, stacked paper as a sheet-like recording medium, more particularly, to an option-type paper feeding device, the device itself having an inkjet printing function and being structured as a hybrid printing system by being suitably connected to, for instance, a stencil printing apparatus.

2. Description of the Related Art

Stencil printing apparatuses afford high-speed low-cost printing, but can print only one color per drum. In color printing, therefore, it becomes necessary to carry out superposed printing by preparing a plurality of drums (four or more in full-color printing), or to arrange such plural drums in one device. Superposed printing requires time, while simultaneous four-color printing involves highly costly constructions, which are therefore not realized.

Stencil printing uses master plates, and hence has been unsuitable for printing of changeable data in, for instance, page printing, address printing and the like. Common portions have therefore come to be stencil-printed, after which variable portions are printed using a printer or the like, but this approach cannot avoid the hassle and time expense involved.

For instance, Japanese Patent Application Laid-open Nos. 2002-137514 and 2002-137515 disclose a hybrid stencil printing apparatus, comprising a stencil printing section and an inkjet printing section that is different from the stencil printing section, the hybrid stencil printing apparatus being capable of performing color printing in one single paper run. To counter the influence of the printing speed difference between the stencil printing section and the inkjet printing section, a transport stretch that is longer than the largest paper size is provided between the two printing sections. However, providing a stencil printing section and an inkjet printing section in one apparatus is problematic in that, for instance, the resulting hybrid printing system cannot be built using an already-existing stencil printing apparatus, and in that the hybrid stencil printing apparatus requires troublesome maintenance in terms of, for instance, inkjet head cleaning and replacement.

Moreover, Japanese Patent Application Laid-open No. 2002-60072 discloses a hybrid image forming apparatus in which a post-processing device, comprising an inkjet recording medium device, is connected to the body of the image forming apparatus, and in which an electrophotographic image forming section is constructively separated from an inkjet printing section.

Also, Japanese Patent Application Laid-open No. 2006-76043 discloses a hybrid stencil printing apparatus in which an inkjet printing section is provided in a unit exposed outside the apparatus.

Japanese Patent Application Laid-open No. 2005-41631 (US 2005/0017430) discloses a hybrid stencil printing apparatus in which a high-volume paper feeding unit, having an inkjet printing section, is connected to a stencil printing apparatus. This hybrid stencil printing apparatus allows constructing a hybrid printing system using an already-existing stencil printing apparatus, and enables fast and high-volume color printing that is compatible with variable data. As a further advantage, maintenance of the inkjet heads is straightforward.

The transport speed in the printing section of inkjet printing devices is ordinarily constant. Adjusting and controlling the ink discharge rate becomes thus complex when the transport speed is variable. When constructing a hybrid printing system (hybrid stencil printing apparatus or the like) in which an option-type paper feeding device, having an inkjet printing section, is connected to a printing apparatus such as a stencil printing apparatus or the like, therefore, the transport speed (printing speed) has to be matched to the transport speed of the inkjet printing section, and thus the option-type paper feeding device cannot be connected to a printing apparatus with which transport speed is not matched.

Printing speed can be arbitrarily set in the stencil printing apparatus, but in the case of conventional option-type paper feeding devices having an inkjet printing section, the printing speed is matched to that of the paper feeding device, and hence printing can only be carried out at the printing speed of the paper feeding device. It becomes thus impossible to reap the benefits of a printing apparatus having multiple printing speeds.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an option-type paper feeding device that can contribute to enhancing printing operation efficiency while taking advantage of variable printing speed in a printing apparatus.

In an aspect of the present invention, an option-type paper feeding device comprises a paper stacking section; a paper feeding mechanism for separating and feeding, sheet by sheet, paper from the paper stacking section; an intermediate transport section, arbitrarily connectable to a paper feeding section of a printing apparatus for printing in use of a plate, for transporting the paper fed by the paper feeding mechanism towards the paper feeding section of the printing apparatus; and an inkjet printing section provided in the intermediate transport section. The intermediate transport section comprises a first paper transport device provided facing the inkjet printing section, and a second paper transport device provided downstream in a transport direction of the first paper transport device, and a transport speed of the first paper transport device is fixed to a substantially constant speed, and a transport speed of the second paper transport device is variable.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompanying drawings in which:

FIG. 1 is a front-view diagram illustrating the schematic constitution of a high-volume paper feeding device as an option-type paper feeding device according to a first embodiment of the present invention;

FIG. 2 is a diagram illustrating the schematic constitution of an intermediate transport section of the high-volume paper feeding device;

FIG. 3 is a block diagram illustrating the configuration of a control system of the high-volume paper feeding device;

FIG. 4 is a schematic diagram illustrating the flow of ink from an ink bottle to a waste liquid tank;

FIG. 5 is a front-view diagram illustrating the schematic constitution of a hybrid stencil printing system in which a high-volume paper feeding device and a high-volume paper discharge device are connected to a stencil printing apparatus;

FIG. 6 is a front-view diagram illustrating the schematic constitution of an inkjet printer according to a second embodiment of the present invention, in which a high-volume paper feeding device and a high-volume paper discharge device are connected together;

FIG. 7 is a front-view diagram illustrating the schematic constitution of a stencil printing apparatus according to the present invention;

FIG. 8 is a block diagram illustrating the configuration of a control system of the stencil printing apparatus; and

FIG. 9 is a perspective-view diagram illustrating the constitution of a characterizing portion of an operation panel of the stencil printing apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT(s)

Embodiments of the present invention are explained below with reference to accompanying drawings.

A first embodiment of the present invention will be explained first based on FIGS. 1 to 5.

As illustrated in FIGS. 1 and 2, a high-volume paper feeding device 200, as an option-type printing device, comprises for instance a paper stacking section 201 on which printing paper can be stacked in larger amounts than in sheet feeding trays or paper feeding trays that are provided, as standard equipment, in printing apparatuses such as stencil printing apparatuses or the like; a paper feeding mechanism 202 for separating and feeding, sheet by sheet, paper 166 from the paper stacking section 201; and an intermediate transport section 203 for transporting the paper 166 fed by the paper feeding mechanism 202 towards a paper feeding tray of a paper feeding section of a below-described stencil printing apparatus.

The intermediate transport section 203 comprises an inkjet printing section 204; a first paper transport means 205 provided below the inkjet printing section 204, extending substantially horizontally facing the inkjet printing section 204; and a second paper transport means 206 provided downstream in the transport direction of the first paper transport means 205.

The paper 166 is stacked on a paper feeding tray 162 of the paper stacking section 201. The paper feeding tray 162, having paper stacked thereon, is moved up and down, between a lower-limit position and an upper-limit position, by a paper feeding tray raising and lowering mechanism not shown. In FIG. 1, the reference numeral 160 denotes a bottom plate, the reference numeral 161 a paper size detection sensor for detecting paper size in the paper feeding direction, and the reference numeral 163 a side fence. A sensor, not shown, is provided also for detecting paper size in the paper width direction, which is perpendicular to the paper feeding direction.

The paper feeding mechanism 202 comprises, for instance, a paper feeding roller 164 a, a separation roller 164 b, a separation pad 165 and a stepping motor not shown. When the paper feeding tray 162, with paper stacked thereon, is raised by the above-described paper feeding tray raising and lowering mechanism from a stop position to an upper-limit position, the uppermost sheet of the paper 166 on the paper feeding tray 162, which has stopped at the upper-limit portion, is separated and transported by the separation roller 164 b and the paper feeding roller 164 a that rotate through the action of the above-described stepping motor, and is transported to the first paper transport means 205.

Four line-type inkjet heads for a respective color are disposed in the inkjet printing section 204. Dedicated heads of four colors including Y (yellow) 42 a, M (magenta) 42 b, C (cyan) 42 c and Bk (black) 42 d supply inks of respective colors to the inkjet printer head.

In the high-volume paper feeding device 200 there are disposed dedicated ink bottles of four colors including an ink bottle Y (yellow) 41 a, an ink bottle M (magenta) 41 b, an ink bottle C (cyan) 41 c and an ink bottle Bk (black) 41 d.

As illustrated in FIG. 3, an ink pump 207 is disposed in each ink bottle. Ink is supplied to each inkjet printer head on the basis of signals from a control means 208 that controls the operation of the high-volume paper feeding device 200. The control means 208 is a microcomputer having, for instance, a CPU, a ROM, a RAM and an I/O interface.

In each ink bottle there is provided an ink residual amount detection sensor 209, as an ink residual amount detection means that outputs a residual ink amount signal to the control means 208. On the basis of this signal, an operation panel 103 of the stencil printing apparatus 300 illustrated in FIG. 9 can display the residual amount of ink. As illustrated in FIG. 3, the residual amount of ink can also be displayed on an operation panel 212 of the high-volume paper feeding device 200.

Waste liquid generated during cleaning of the inkjet printer heads is collected in a waste liquid tank 44 via waste liquid pipes 40 a, 40 b, 40 c, 40 d, as illustrated in FIG. 4. A waste ink full-state detection sensor 210, provided in the waste liquid tank 44, outputs a full-state state signal to the control means 208. On the basis of this signal, the waste liquid full-state can be displayed on the operation panel 103. As illustrated in FIG. 3, the waste liquid full-state can also be displayed on the operation panel 212 of the high-volume paper feeding device 200.

The first paper transport means 205 comprises, for instance, a driving roller 43 a, a driven roller 43 b, an endless belt 43 c as a paper transport member and a suction fan 46 a. The paper 166 transported from the separation roller 164 b is sucked, through air negative pressure, is transported, and is delivered to the second paper transport means 206 on the downstream side. The transport speed of the first paper transport means 205 is fixed at a predefined speed that is suitable for printing in the inkjet printing section 204.

The second paper transport means 206 comprises, for instance, a driving roller 43 d, a driven roller 43 e, an endless belt 43 f as a paper transport member and a suction fan 46 b. In the second paper transport means 206, the paper 166 transported from the first paper transport means 205 is suctioned, through air negative pressure, and is suction-transported up to an end position of the intermediate transport section 203.

The transport speed of the second paper transport means 206 is variable (multi-speed). The control means 208, having obtained printing speed information of a stencil printing apparatus 300 to be described later from a control means 129 of the stencil printing apparatus 300, sets the transport speed of the second paper transport means 206 to an adequate transport speed. That is, the transport speed of the second paper transport means 206 can vary in accordance with the speed of a paper feeding roller and/or a resist roller pair of the stencil printing apparatus 300. The second paper transport means 206 has a speed conversion function between the high-volume paper feeding device 200 and the stencil printing apparatus 300.

Speed adjustment is carried out by controlling the rotation speed of a driving motor 211, as a driving source, that drives the driving roller 43 d, as illustrated in FIG. 3.

The control means 129 of the stencil printing apparatus 300 controls the driving motor 211 via the control means 208.

As illustrated in FIGS. 1 and 2, a press roller 47, for pressing the paper, is provided above the driven roller 43 b, on the upstream end, in the transport direction, of the first paper transport means 205. The press roller 47 presses the paper against the endless belt 43 c.

As described above, the uppermost sheets of the paper 166 stacked on the paper feeding tray 162 are separated and transported, sheet by sheet, by the paper feeding roller 164 a and the separation roller 164 b. During paper transport in the first paper transport means 205, however, the press roller 47 may be pressed, while the paper 166 is separated and transported from the paper feeding mechanism 202. Thereby, paper transport and inkjet printing can be carried out simultaneously, and images can be printed without image shift.

Misregistration between paper and images occurs when the separation and transport speed of the paper feeding mechanism 202 and the paper transport speed of the first paper transport means 205 are not matched. To match the speeds, one of the speeds must be matched to the other. Even if roller diameters, endless belt thickness, working speed of the stepping motor and so forth are all matched, there remain variations in machining precision as regards roller diameters, endless belt thickness and the like. As a result, rotation by the stepping motor may give rise to differences in the respective transport speeds.

To address this problem, high-precision matching between paper transport timings and inkjet printing timings is realized by pressing the press roller 47 while the paper 166 is separated and transported from the paper feeding mechanism 202, in such a manner that there occurs no paper positional offset, by reliably suction-transporting the paper at the transport speed of the first paper transport means 205.

As shown in FIG. 5, the leading end of the intermediate transport section 203 of the high-volume paper feeding device 200 is inserted into, and connected to, a paper feeding section 301 of the stencil printing apparatus 300, as a printing apparatus for printing using a plate. Herein, the paper detection sensor and so forth of the paper feeding section 301 of the stencil printing apparatus 300 are disabled by being blocked by the intermediate transport section 203. Thus, the high-volume paper feeding device 200 takes over the function of the paper feeding section 301.

Needless to say, when the stencil printing apparatus 300 and the high-volume paper feeding device 200 are electrically connected (when the control means 129 and the control means 208 are connected so as to be capable of communicating with each other), paper feeding is controlled by the high-volume paper feeding device 200.

Aside from the paper feeding section 301, paper can also be fed by providing a dedicated connection port (paper feeding section), for connection with to high-volume paper feeding device 200, in the stencil printing apparatus 300. The constitution and printing operation in the stencil printing apparatus 300 are explained in detail further on.

In FIG. 5, the reference numeral 400 denotes a high-volume paper discharge device, as a paper discharge device. The high-volume paper feeding device 200, the stencil printing apparatus 300 and the high-volume paper discharge device 400 are mechanically and electrically connected to make up a hybrid stencil printing system capable of printing in different printing modes (stencil printing plus inkjet printing).

Upon reception of a paper feeding start signal from the control means 129 of the stencil printing apparatus 300, a paper presence detection sensor, not shown, of the paper feeding tray 162 of the high-volume paper feeding device 200 detects whether there is stacked paper or not. If there is stacked paper, the paper feeding tray 162, with paper stacked thereon, is raised by a paper feeding tray raising and lowering mechanism, not shown, from a stop position to an upper-limit position, the paper feeding tray 162 stopping then at the upper-limit position.

The uppermost sheets of the stacked paper 166 are separated, one by one, by the paper feeding roller 164 a and the separation roller 164 b, and are transported to the first paper transport means 205. The first paper transport means 205 maintains, with high precision, the distance between the paper 166 and each inkjet printer head, while transporting the paper 166 in a substantially horizontal direction, during which predetermined printing by the inkjet printing section 204 is carried out on the paper 166. That is, printing by the inkjet printing section 204 is carried out before feeding the paper to the stencil printing apparatus 300.

As a result, variable data portions can be printed by the inkjet printing section 204, while common portions can be printed by the stencil printing apparatus 300.

Suction transport allows herein the inkjet printing section 204 to perform paper transport and inkjet printing at given timings, whereby images can be printed without image shift. Although suction transport by air negative pressure is employed in this case, electrostatic adhesion can also be used.

The inkjet printing section 204 may be a monochrome one, but in the present embodiment inkjet printer heads for respective colors are disposed in the inkjet printing section 204, in such a manner that the latter is capable of full color printing.

Since the inkjet printing section 204 is thus capable of full color printing, the high-volume paper feeding device 200 itself can function as an independent image forming apparatus.

As illustrated in FIG. 3, the high-volume paper feeding device 200 has a cleaning means 213 for cleaning the various inkjet printer heads of the inkjet printing section 204. The cleaning operation of the inkjet heads in the inkjet printing section 204 of the high-volume paper feeding device 200 is carried out in response to an instruction from the control means 129 of the stencil printing apparatus 300 or from the control means 208 of the high-volume paper feeding device 200.

During mass printing, the cleaning operation can be carried out depending on the number of print sheets, or during a temporary printing stop, as a countermeasure against nozzle clogging caused by paper dust during continuous printing.

A second embodiment is explained next on the basis of FIG. 6.

Elements identical to those of the first embodiment above are denoted with identical reference numerals. Unless otherwise necessary, features and functions already explained will be omitted in the explanation, which will focus only on relevant portions.

In the second embodiment, the high-volume paper feeding device 200 is not connected to the stencil printing apparatus 300, but directly to the high-volume paper discharge device 400, to make up thereby an inkjet printer.

The high-volume paper discharge device 400 may be an offline paper discharge device in which a paper discharge tray 73 is lowered for a given time when an upper-limit detection sensor, not shown, detects a paper discharge upper limit on the paper discharge tray 73. The paper discharge tray 73 is lowered down to a lower limit position detected by a detection sensor not shown.

The paper, having been printed in full color printing (inkjet printing) by the high-volume paper feeding device 200, is transported to the high-volume paper discharge device 400 where it is stacked on the paper discharge tray 73. In FIG. 6, the reference numeral 71 denotes an upper plate, 70 a bottom plate, 72 an end fence and 74 a side fence of the device body.

When the high-volume paper feeding device 200 and the high-volume paper discharge device 400 are connected so as to be capable of communicating with each other, the downward movement of the paper discharge tray 73 is discontinued upon reaching the lower-limit position, whereupon a signal indicating that the paper discharge tray is full is sent to the control means 208 of the high-volume paper feeding device 200. Upon reception of the signal indicating that the paper discharge tray is full, the control means 208 of the high-volume paper feeding device 200 displays, on the operation panel 212, that the paper discharge tray is full.

The high-volume paper discharge device 400 comprises a transport jam detection sensor not shown. Upon detecting a paper transport jam, the transport jam detection sensor sends a transport jam signal to the high-volume paper feeding device 200. Upon receiving the transport jam signal, the control means 208 displays a paper jam notice on the operation panel 212, and stops the paper feeding operation of the high-volume paper feeding device 200.

When the high-volume paper feeding device 200 is directly connected to the high-volume paper discharge device 400, print data inputted or transmitted by, for instance, a LAN, a removably disk or the like is stored in an internal memory (ROM or the like) of the control means 208. The print data can be printed later in the high-volume paper feeding device 200. During printing, data can be used for printing by being read from the internal memory in the control means 208.

By setting a print sheet count and pressing a print key in the operation panel 212, thus, data read out of the internal memory in the control means 208 can be additionally printed in the high-volume paper feeding device 200 after printing of a set number of print sheets of transmitted or inputted print data.

The constitution and printing operation of the stencil printing apparatus 300 illustrated in the first embodiment will be explained next with reference to FIGS. 7 to 9.

As illustrated in FIG. 7, the stencil printing apparatus 300 comprises, for instance, a printing section 15, a platemaking section 40, a paper feeding section 301, a plate discharging section 80, a paper discharge section not shown, an image reading section 50 and paper separation pawls 17.

The printing section 15, disposed substantially in the center of the stencil printing apparatus 300, comprises a plate cylinder 1 and a press roller 13. The plate cylinder 1 comprises mainly a pair of end plates, not shown, rotatably supported on a pivot shaft 16 that doubles as an ink supply pipe, a porous support plate, not shown, wrapped around the outer peripheral face of the end plates, and a mesh screen, not shown, wrapped around the outer peripheral face of the porous support plate. The plate cylinder 1, which is rotationally driven by plate cylinder driving means 121 (FIG. 8), is detachably mountable on the stencil printing apparatus 300.

The size of the plate cylinder 1 in the present embodiment is such so as to allow obtaining printed products of a maximum A3 size during one-side printing. An ink supply means 18 is provided inside the plate cylinder 1. The ink supply means 18 comprises, for instance, the pivot shaft 16, an ink roller 3, a doctor roller 4 and so forth. The ink roller 3 is rotatably supported between side plates, not shown, provided in the plate cylinder 1. The peripheral face of the ink roller 3 is disposed in the vicinity of the inner peripheral face of the plate cylinder 1. The ink roller 3 is rotationally driven by driving means, not shown, in the same direction as the plate cylinder 1.

The doctor roller 4 is also rotatably supported between the above-described side plates. The peripheral face of the doctor roller 4 is disposed in the vicinity of the peripheral face of the ink roller 3. The doctor roller 4 is rotationally driven by driving means, not shown, in an opposite direction to that of the plate cylinder 1.

A plurality of small holes are opened in the pivot shaft 16, such that the supplied ink accumulates in a space of wedge-like cross section that forms in the vicinity of the ink roller 3 and the doctor roller 4, to form a liquid pool.

A stage, not shown, that follows a plane along one generatrix of the plate cylinder 1, is formed on the peripheral face of the plate cylinder 1. A damper 6, for holding a leading end of a master 2, is disposed on the outer peripheral face of the plate cylinder 1. The damper 6, which rotates supported on a rotary shaft 5 as a pivot shaft, is opened and closed by an opening and closing means, not shown, when the plate cylinder 1 rotates up to a predetermined position.

The press roller 13 is disposed below the plate cylinder 1. The press roller 13, which comprises an elastic body such as rubber or the like wrapped around a metal core, is disposed extending in the axial direction of plate cylinder 1. Two ends of a core, not shown, of the press roller 13 are rotatably supported by a pair of arm members not shown.

The substantially L-shaped arm members are integrally formed by way of a swinging shaft, not shown, mounted at a position in the vicinity of bent parts of the arm members. The swinging shaft, not shown, is swingably supported on the body of the stencil printing apparatus 300.

The peripheral face of the press roller 13 occupies a separated position from the peripheral face of the plate cylinder 1 when the protrusions of cam plates, not shown, abut cam followers not shown. The peripheral face of the press roller 13 occupies a pressure-contact position against the peripheral face of the plate cylinder 1, on account of the urging force of a pressing spring, not shown, when the abutting of either of the protrusions and the cam follower, not shown, is released.

The platemaking section 40 is disposed at the right upper portion of the stencil printing apparatus 300. The platemaking section 40 comprises, for instance, a master holding member 41, a platen roller 42, a thermal head 43, a cutting means 44, a master stocking section 45, a tension roller pair 46 and a reversing roller pair 48.

The master holding member 41 is provided at a pair of side plates, not shown, of the platemaking section 40. The master holding member 41 rotatably and detachably holds both ends of a core of a master roll around which there is wrapped a master that comprises a thermoplastic resin film bonded to a porous support. A platen roller 42, not shown, provided on the left of the master holding member 41, is rotatably supported on a side plate, not shown, of the platemaking section 40. The platen roller 42 is rotationally driven by a platemaking driving means 124 (FIG. 8) that comprises a stepping motor not shown. The thermal head 43, positioned below the platen roller 42 and comprising multiple thermal elements, is mounted also on a side plate, not shown, of the platemaking section 40. The surfaces of the thermal elements are brought into pressure contact with the platen roller 42, on account of the pressing force exerted by pressing means not shown.

The thermal head 43 perforates the master, through thermal fusion, by bringing the thermal elements into contact with the surface of the thermoplastic resin film of the master, and by selectively activating then heat generation in the thermal elements. The cutting means 44 is disposed on the left of the platen roller 42 and the thermal head 43.

The cutting means 44, not shown, comprises a fixed blade fixedly provided on a frame, not shown, of the platemaking section 40, and a movable blade that is movably supported on the fixed blade. The cutting means 44 has thus a well-known constitution for cutting a master by rotationally moving the mobile blade relative to the fixed blade.

The master stocking section 45 is disposed below the cutting means 44, on the downstream direction of the master transport direction. The interior of the master stocking section 45, as a space in which the prepared master is stored for a while, is partitioned by a plurality of plate members. A suction fan, not shown, is arranged at the innermost portion of the master stocking section 45. Driving of the suction fan generates a negative pressure in the interior of the master stocking section 45, which is an airtight space, whereby the prepared master, transported up to the master stocking section 45, is stored in the innermost portion of the latter.

The tension roller pair 46 is disposed at a position between the cutting means 44 and the master stocking section 45. The tension roller pair 46 comprises a driving roller and a driven roller rotatably supported on respective side plates, not shown, of the platemaking section 40. The peripheral face of the driven roller is brought into pressure contact with the peripheral face of the driving roller through the action of pressing means not shown. The driving roller is rotationally driven by the platemaking driving means 124, to clamp and transport the master.

The peripheral speed of the driving roller is set to be slightly faster than the peripheral speed of the platen roller 42. A torque limiter, not shown, is provided inside the driving roller. The platen roller 42 and the tension roller pair 46 are configured so as to apply a predetermined tension to the master.

The reversing roller pair 48, which is disposed on the downstream side of the master transport direction in the master stocking section 45, comprises a driving roller and a driven roller rotatably supported on respective side plates, not shown, of the platemaking section 40. The reversing roller pair 47 clamps and transports the master by way of the driving roller, which is rotationally driven by the platemaking driving means 124, and the driven roller, which is disposed so as to be brought into pressure contact with the driving roller by pressing means not shown.

A one-way clutch, not shown, is provided inside the driving roller. A movable master guide plate, not shown, is disposed at a position between the tension roller pair 46 and the reversing roller pair 48. The movable master guide plate is swingably supported on support members not shown. The top face of the movable master guide plate can be selectively positioned, by way of a solenoid not shown, between a transport position, at which the movable master guide plate forms a master transport path, and a retreat position at which the movable master guide plate does not hamper insertion of the master into the master stocking section 45.

The paper feeding section 301 is disposed below the platemaking section 40. The paper feeding section 301 comprises, for instance, a paper feeding tray 60, a paper feeding roller 10 a, a separation roller 10 b, a separation pad 11, a resist roller pair 12 and so forth. The paper feeding tray 60, onto the top face whereof multiple paper sheets 100 can be stacked, is supported so as to be movable up and down the body of the stencil printing apparatus 300. The paper feeding tray 60 is raised and lowered by a paper feeding driving means 125 (FIG. 8) that comprises raising and lowering means.

On the top face of the paper feeding tray 60, where paper 100 of A3 size can be vertically set, there is provided a pair of side fences 62 supported so as to be movable on the paper width direction, which is perpendicular to the paper transport direction, along rail members not shown.

Plural paper size detection sensors 61, for detecting the size of the stacked paper 100, are provided at the free end side of the paper feeding tray 60.

The paper feeding roller 10 a, having on the surface thereof a high friction resistance member, is disposed above the paper feeding tray 60. The paper feeding roller 10 a is rotatably supported on a bracket, not shown, that is swingably supported on the body of the stencil printing apparatus 300. The paper feeding roller 10 a is brought into pressure contact with the paper 100 at the uppermost position of the paper feeding tray 60, with a predetermined pressure contact force, when the paper feeding tray 60 is raised by a raising and lowering means not shown. The paper feeding roller 10 a is rotationally driven by a paper feeding driving means not shown.

On the left of the paper feeding roller 10 a there are disposed the separation roller 10 b and the separation pad 11 comprising, on the surface thereof, a high friction resistance material. The separation roller 10 b is drivingly connected to the paper feeding roller 10 a by way of a timing belt, such that when the paper feeding roller 10 a is rotationally driven, the separation roller 10 b is rotationally driven in synchrony with the paper feeding roller 10 a, in the same direction as the latter.

The separation pad 11 is brought into pressure contact with the separation roller 10 b on account of the urging force of an urging means not shown. The resist roller pair 12 is disposed on the left of the separation roller 10 b and the separation pad 11. The resist roller pair 12 comprises a driving roller 12 b and a driven roller 12 a. The driving roller 12 b rotates with a predetermined timing, in synchrony with the plate cylinder 1, on account of a rotational driving force from the plate cylinder driving means 121 that is transmitted via a driving force transmission means, not shown, comprising gears, cams or the like, while the driven roller 12 a is brought into pressure contact with the driving roller 12 b, as a result of which the paper 100 is fed towards the printing section with a predetermined timing.

Paper feeding guide plates, for guiding the paper 100 that is fed from the paper feeding section 301 to the printing section 15, are respectively disposed on the upstream and downstream sides of the paper transport direction of the resist roller pair 12. The paper feeding guide plates are fixed between side plates, not shown, of the body of the stencil printing apparatus 300.

The plate discharging section 80 is disposed above and to the left of the printing section 15. The plate discharging section 80 comprises, for instance, an upper plate discharging member 81, a lower plate discharging member 82, a plate discharge box 83 and a compression plate 84. The upper plate discharging member 81 comprises, for instance, a driving roller, a driven roller and an endless belt. In the upper plate discharging member 81, the driving roller is rotationally driven, in the clockwise direction of the figure, by a plate discharging driving means 126 (FIG. 8), to move thereby the endless belt.

The lower plate discharging member 82 comprises, for instance, a driving roller, a driven roller and an endless belt. In the lower plate discharging member 82, the driving roller is rotationally driven, in the counterclockwise direction of the figure, by the driving force of the plate discharging driving means 126, which rotationally drives the driving roller, the driving force being transmitted to the driving roller via a driving force transmission means, not shown, comprising gears, cams or the like. The driving roller, thus rotationally driven, causes the endless belt to move.

The lower plate discharging member 82 is movably supported thanks to a moving means, not shown, comprised in the plate discharging driving means 126. The lower plate discharging member 82 can occupy the position illustrated in the figure and a position at which the endless belt, positioned on the outer peripheral face of the driven roller, abuts the outer peripheral face of the plate cylinder 1.

The plate discharge box 83, in which the used master is stored, is removably provided in the body of the stencil printing apparatus 300. The compression plate 84 for compressing, into the plate discharge box 83, the used master that is transported by the upper plate discharging member 81 and the lower plate discharging member 82, is supported on the body of the stencil printing apparatus 300 in such a way so as to be movable up and down. The compression plate 84 is moved up and down by a raising and lowering means, not shown, comprised in the plate discharging driving means 126.

A paper discharge section 20 is disposed below the plate discharging section 80. The paper discharge section 20 comprises, for instance, the paper separation pawls 17, a discharge paper transport unit 21 and a discharge paper tray 70.

The paper separation pawls 17 are provided in the width direction of the plate cylinder 1. The paper separation pawls 17 are integrally mounted on a pivot shaft that is swingably supported on the body of the stencil printing apparatus 300. The paper separation pawls 17 are swung by a pawl swinging means, not shown, in such a manner that the ends of the paper separation pawls 17 selectively occupy a position, illustrated in the figure, in the vicinity of the outer peripheral face of the plate cylinder 1, and a position at which the ends of the paper separation pawls 17 are separated from the outer peripheral face of the plate cylinder 1 in order to avoid obstacles such as the damper 6 or the like.

The driving force from the plate cylinder driving means 121 (FIG. 8) is transmitted, via driving force transmission means, not shown, to the pawl swinging means not shown, as a result of which the paper separation pawls 17 are swung in synchrony with the rotation of the plate cylinder 1.

The discharge paper transport unit 21, disposed below and to the left of the paper separation pawls 17, comprises driving rollers 25 b, driven rollers 25 a, endless belts 27 and a suction fan 26. The plural driving rollers 25 b are mounted, with predetermined spacings, on a pivot shaft, not shown, that is rotatably supported on a unit side plate not shown. The driving rollers 25 b are rotationally driven in unison by a paper discharge driving means 127 (FIG. 8).

The driven rollers 25 a are likewise mounted, with spacings identical to those of the driving rollers 25 b, on a pivot shaft, not shown, that is rotatably supported on the unit side plate. The endless belts 27 are wound around respective driving rollers 25 b and the corresponding driven rollers 25 a. The suction fan 26 is disposed below the driving rollers 26 b, the driven rollers 25 a and the endless belts 27.

In the discharge paper transport unit 21, the printed paper 101 on the endless belts 27 is sucked by the suction force of the suction fan 26, and is transported on account of the rotation of the driving rollers 25 b. The printed paper 101 transported by the discharge paper transport unit 21 is stacked on the top face of the discharge paper tray 70, which has one end fence 71 that is movable in the paper transport direction, and a pair of side fences 72 that are movable in the paper width direction.

The image reading section 50 is disposed above the stencil printing apparatus 300. The image reading section 50 comprises, for instance, a contact glass 52 on which a document is set; a pressure plate 51 separably provided on the contact glass 52; reflecting mirrors and a fluorescent lamp for scanning and reading document images; a lens 53 for condensing a scanned document image; an image sensor 54 such as a CCD or the like for processing the condensed image; a plurality of document size detection sensors 55, for detecting document size; and an image memory, not shown, for storing the read image data. Reading of document images is performed through the operation of a reading driving means 128 not shown (refer to FIG. 8) As illustrated in FIG. 7, a dog 29 is mounted on the outer face of an end plate, not shown, comprised in the plate cylinder 1. A home position sensor 28 is mounted on the body of the stencil printing apparatus 300, in the vicinity of the periphery of the plate cylinder 1. When the plate cylinder 1 occupies a position where the clamper 6 stands opposite the press roller 13, the home position sensor 28 detects the dog 29, and sends a corresponding signal to the control means 129.

FIG. 9 illustrates the operation panel of the stencil printing apparatus 300. In the figure, the top face of the operation panel 103 provided in the upper front face of the stencil printing apparatus 300 comprises, for instance, a platemaking start key 104, a print start key 105, a test print key 106, a consecutive mode key 107, a clear/stop key 108, a numerical keypad 109, an enter key 110, a program key 111, a mode clear key 112, a printing speed setting key 113, four direction keys 114, a paper size setting key 115, a paper thickness setting key 116, a display device 119 comprising a 7-segment LED, and a display device 120 comprising an LCD.

The platemaking start key 104 is pressed to launch the platemaking operation in the stencil printing apparatus 300. When the platemaking start key 104 is pressed, the platemaking operation is carried out after plate discharge and document reading have been performed. A plate fixing operation is carried out thereafter, whereupon the stencil printing apparatus 300 is brought to print standby.

The print start key 105 is pressed to launch the printing operation in the stencil printing apparatus 300. When the stencil printing apparatus 300 is in print standby, and after setting the various printing conditions, the printing operation is carried out upon pressing the print start key 105. The test print key 106 is pressed to carry out a test print in the stencil printing apparatus 300. After setting the various conditions, a single test sheet is printed upon pressing the test print key 106. The consecutive mode key 107 is pressed, prior to pressing the platemaking start key 104, when the platemaking operation and the printing operation are to be carried out consecutively. After pressing the consecutive mode key 107 and inputting the printing conditions, pressing the platemaking start key 104 causes the print operation to be carried out following the plate discharge operation, the document reading operation and the platemaking operation.

The clear/stop key 108 is pressed to stop the platemaking operation or to clear a register in the stencil printing apparatus 300. The numerical keypad 109 is used for inputting numerical values. The enter key 110 is pressed to set numerical values or the like during the various setups, and the program key 111 is pressed for recording and/or calling frequently executed operations. The mode clear key 112 is pressed to clear the various modes and to return to an initial state.

The printing speed setting key 113 is pressed to set a printing speed, before the printing operation. A slower printing speed is set, for instance, when more vivid images are desired, or when atmospheric temperature is low, while a faster printing speed is set, for instance, when attenuated images are desired, or when atmospheric temperature is high.

The four direction keys 114 include an upper key 114 a, a lower key 114 b, a left key 114 c and a right key 114 d. The direction keys are pressed, for instance, to adjust image position during image editing, or for selecting numerical values or items during the various setups.

The paper size setting key 115 is pressed for inputting an arbitrary paper size. The paper size inputted via the paper size setting key 115 has priority over the paper size detected by the paper size detection sensor 61. The paper thickness setting key 116 is pressed for inputting the thickness of the paper 100 prior to two-side printing. In the present embodiment there can be selected three types of thickness among “ordinary paper”, “thin paper” and “thick paper”.

The display device 119, comprising a 7-segment LED, displays mainly a print sheet count and the like. The display device 120 comprising an LCD has a hierarchical display structure. The selection keys key 120 a, 120 b, 120 c, 120 d provided below the display device 120 are pressed to allow switching between various modes such as scaling, position adjustment and the like, and to allow setting up the various modes. In addition to the display of the status of the stencil printing apparatus 300, to the effect of “platemaking/printing enabled” illustrated in the figure, the display device 120 can display also an alarm in case of platemaking or plate discharge jams, paper feeding or paper discharge jams or the like, as well as indications for replenishing print paper, masters, ink and so forth.

FIG. 8 is a control block diagram of the stencil printing apparatus 300. In the figure, the control means 129, which is well-known microcomputer having, for instance, a CPU 130, a ROM 131 and a RAM 132, is provided in the body of the stencil printing apparatus 300.

On the basis of the various signals inputted via the operation panel 103, the detection signals from the various sensors provided in the body of the stencil printing apparatus 300, as well as the operation program called from the ROM 131, the CPU 130 controls the various driving means provided in the printing section 15, the platemaking section 40, the paper feeding section 301, the plate discharging section 80, the paper discharge section 20 and the image reading section 50, to control the entire operation of the stencil printing apparatus.

The operation programs of the entire stencil printing apparatus are stored in the ROM 131. The operation programs can be arbitrarily called by the CPU 130. The RAM 132 has, for instance, the function of temporarily storing computation results of the CPU 130, and of storing, on demand, on/off signals and data signals that are set and inputted by the various sensors and the various keys on the operation panel 103.

The control means 129, moreover, grasps the position of the plate cylinder 1 on the basis of home position signals from a home position sensor 134 and signals from an encoder, not shown, provided in the plate cylinder driving means 121.

The operation of the stencil printing apparatus 300 is explained next on the basis of the above constitution.

The operator stacks paper 100, used for printing, on the paper feeding tray 60, opens the pressure plate 51, sets the document to be printed on the contact glass 52, and closes then the pressure plate 51. Thereafter, the operator sets up the platemaking conditions by way of the various keys on the operation panel 103, and presses then the platemaking start key 104.

An instance of one-side printing, through pressing of the one-side printing key 118, will be explained first. The operator presses the platemaking start key 104. When the platemaking start key 104 is pressed, a paper size detection signal from the paper size detection sensor 61, and a document size detection signal from the document size detection sensor 55 are sent to the control means 129, which compares the received signals.

When the paper size is identical to the document size, the image reading operation is carried out immediately. When the paper size is different from the document size, the control means 129 displays a notice to that effect on the display device 120, to warn the operator. When the paper size and the document size are different, magnification or reduction scaling may be automatically carried out following an instruction from the control means 129, in such a way so as to match document size and image size.

When the platemaking start key 104 is pressed, the reading operation of the document images is carried out in the image reading section 50. Reflection light exposed by a fluorescent lamp is reflected at various reflective mirrors. The read document image is condensed by the lens 53 and strikes then the image sensor 54, to carry out document image reading by photoelectric conversion.

The electric signals resulting from photoelectric conversion are inputted into an A/D converter, not shown, and are stored then in an image memory 135 as image data signals.

In parallel to the image reading operation in the image reading section 50 there is carried out a plate discharge operation at the plate discharging section 80, where a used master is separated from the outer peripheral face of the plate cylinder 1. The plate cylinder 1 starts rotating when the platemaking start key 104 is pressed. When the plate cylinder 1 reaches the home position illustrated in FIG. 7, the dog 29, not shown, in the figure is detected by the home position sensor 28, whereupon the home position sensor 28 sends a home position signal to the control means 129.

Having received the home position signal, the control means 129 measures the number of pulses generated by an encoder, not shown, taking the home position as a reference. The control means 129 discontinues the operation of the plate cylinder driving means 121 when the control means 129 judges that the leading end of the used master wrapped on the outer peripheral face of the plate cylinder 1 has reached a predefined plate discharge position, opposite the endless belt on the outer peripheral face of the driven roller of the plate discharging section 80.

When the plate cylinder driving means 121 stops, and the plate cylinder 1 stops as a result at a predefined plate discharge position, the plate cylinder driving means 121 and the plate discharging driving means 126 operates to rotationally drive the respective driving rollers and to move the lower plate discharging member 82 towards the plate cylinder 1, whereby the endless belt on the outer peripheral face of the driven roller abuts the used master on the plate cylinder 1.

The used master, scooped up from the outer peripheral face of the plate cylinder 1 through the rotation of the plate cylinder 1 and the movement of the endless belt, is sandwiched and transported between the lower plate discharging member 82 and the upper plate discharging member 81, becoming thereby separated from the outer peripheral face of the plate cylinder 1. The separated used master is disposed inside the plate discharge 83, where it is compressed by the compression plate 84.

The plate cylinder 1 continues rotating, after the used master has been completely separated from the outer peripheral face of the plate cylinder 1, until the damper 6 reaches an upper-right plate feeding standby position, whereupon the plate cylinder 1 stops.

When the plate cylinder 1 stops at the plate feeding standby position, an opening and closing means, not shown, operates to open the damper 6, which is thus brought into plate feeding standby. The platemaking operation is carried out in the platemaking section 40 in parallel to the plate discharge operation. When the platemaking start key 104 is pressed, a master is drawn from the master roll as a result of the rotational driving of the platen roller 42, the tension roller pair 46 and the reversing roller pair 47.

The movable master guide plate, not shown, becomes positioned at a transport position. When the image forming region of the drawn master reaches a position facing the thermal elements of the thermal head 43, the image data signals stored in the image memory, not shown, are called after being subjected to image processing. A thermal head driver, not shown, selectively causes the thermal elements of the thermal head 43 to generate heat, to form thereby a platemaking image on the surface of the thermoplastic resin film of the master.

The master is transported as it is being perforated, and when the leading end of the master is clamped by the reversing roller pair 47, the movable master guide plate, not shown, moves to a retreat position, and the rotation of the reversing roller pair 47 stops.

The platen roller 42 and the tension roller pair 46 go on rotating after the reversing roller pair 47 stops rotating, whereby the prepared master, perforated by the thermal head 43, becomes stored in the master stocking section 45.

When the reversing roller pair 47 stops, a suction fan, not shown, provided in the master stocking section 45 operates to suction the prepared master and to afford thus good master storage in the master stocking section 45.

When in the above platemaking operation the stencil printing apparatus 300 is in the plate feeding standby state after the plate discharge operation is over, the reversing roller pair 47 starts rotating, whereupon the prepared master stored in the master stocking section 45 is transported between the stage, not shown, and the open damper 6.

When the leading end of the prepared master is transported up to a predefined position at which the leading end can be clamped by the damper 6, the opening and closing means, not shown, operate to close the damper 6, whereupon the leading end of the master is held against the outer peripheral face of the plate cylinder 1 by the damper 6 and the stage not shown.

The plate cylinder 1 is rotationally driven intermittently in the clockwise direction in FIG. 7, as a result of which the prepared master becomes wrapped around the plate cylinder 1. Thereupon, the rotation of the reversing roller pair 47 stops, and the one-way clutch, not shown, provided in the driving roller, not shown, co-rotates accompanying the drawing of the prepared master.

When the image data signal from the image memory is interrupted, the operation of the thermal head 43 stops. When the one prepared master is transported, the rotation of the platen roller 42, the tension roller pair 46 and the reversing roller pair 47 stops, and the cutting means 44 operates to cut off the prepared master.

The prepared master thus cut off is drawn out of the platemaking section 40 through the rotation of the plate cylinder 1. The plate cylinder 1 rotates up to the home position, where it stops, to conclude the platemaking operation and the plate feeding operation. The plate fixing operation follows then on the plate feeding operation.

When the plate cylinder 1 stops at the home position, the paper separation pawls 17 become positioned in the vicinity of the peripheral face of the plate cylinder 1, whereafter a press roller locking means and a stepping motor, not shown, operate to cause a stepped cam to rotate, whereupon a abuts a cam follower. As a result, a movable arm swings around a pivot shaft, and a camshaft moves to a position at which a cam plate can abut a cam follower. Thereafter, the action of the press roller locking means, not shown, is disabled.

Next, the paper feeding roller 10 a, the separation roller 10 b, the driving rollers 25 a and the suction fan 26 are driven while the plate cylinder 1 is rotationally driven, at low speed, in the clockwise direction of FIG. 7, whereupon the uppermost sheet of the paper 100 stacked on the paper feeding tray 60 is drawn and the leading end of the sheet is clamped by the resist roller pair 12.

The resist roller pair 12 is rotationally driven with the predetermined timing with which the leading end portion in the plate cylinder rotation direction of the image forming region of the prepared master, wrapped around the plate cylinder 1, reaches a position corresponding to the press roller 13, whereupon the drawn paper 100 is fed between the plate cylinder 1 and the press roller 13.

A camshaft, not shown, and a multi-stage cam, not shown, formed integrally with the camshaft, are rotationally driven by way of a press roller contact/separation mechanism 155 in synchrony with the rotation of the plate cylinder 1. A protrusion of the cam plate, not shown, having moved as described above to a position where it can abut the cam follower, not shown, is released from the cam follower, not shown, with the above-described predetermined timing.

As a result, the peripheral face of the press roller 13 is pressed against the outer peripheral face of the plate cylinder 1, through the urging force of a pressing spring, not shown, so that the paper 100 fed by the resist roller pair 12 is pressed against the master that is wrapped around the plate cylinder 1.

Through this pressing operation, the press roller 13, the paper 100, the prepared master and the plate cylinder 1 are brought into pressure contact with one another, whereupon the ink supplied by the ink roller 3 to the inner peripheral face of the plate cylinder 1 bleeds out through openings in the plate cylinder 1. The ink fills the porous support plate, not shown, and the mesh screen, not shown, comprised in the plate cylinder 1, as well as the porous support of the prepared master that is wrapped around the plate cylinder 1, and is transferred to the paper 100, via the perforated portions in the prepared master, in a so-called plate fixing operation.

The paper 100 becomes printed paper 101 by having had printed thereon a platemaking image during plate fixing. The leading end portion of the printed paper 101 is separated from the prepared master, on the outer peripheral face of the plate cylinder 1, through the action of the paper separation pawls 17.

The printed paper 101 thus separated moves downward to be fed to the discharge paper transport unit 21. There, the printed paper 101 hugs the top face of the endless belt 27, on account of the suction force of the suction fan 26, while being transported leftwards, to be outputted onto the discharge paper tray 70. Thereafter, the plate cylinder 1 rotates again up to the home position, where it stops, to finish thereby the plate fixing operation, and bringing the stencil printing apparatus 300 to print standby.

Once the stencil printing apparatus 300 is in print standby, and after the printing conditions have been inputted via the printing speed setting key 113 and the various keys on the operation panel 103, a test print is carried out by pressing the test print key 106. When the test print key 106 is pressed, the plate cylinder 1 is rotationally driven at the set printing speed, and one sheet of paper 100 is fed out of the paper feeding section 301.

The fed paper 100 stops temporarily at the resist roller pair 12. Thereafter, the paper is transported with the same timing as the plate fixing time, and is brought, by the press roller 13, into pressure contact with the prepared master on the outer peripheral face of the plate cylinder 1. The paper separation pawls 17 separate the printed paper 101, having had an image printed thereon, from the prepared master on the outer peripheral face of the plate cylinder 1. The printed paper 101 is then transported by the discharge paper transport unit 21 and is outputted onto the discharge paper tray 70.

Once image position, density and so forth are checked on the test print, and after inputting the number of print sheets via the numerical key pad 109, the print start key 105 is pressed, whereupon paper 100 is continuously fed out of the paper feeding section 301, to carry out the printing operation under the same conditions as in the test print. Once the set number of print sheets has been processed, the plate cylinder 1 stops at the home position, whereby the stencil printing apparatus 300 is brought again to print standby.

The present invention allows matching the paper transport speed and the printing speed in the printing device after the paper has been printed by the inkjet printing section, in the paper feeding device. As a result, the invention succeeds in providing a hybrid printing system with enhanced usability and operational efficiency, in which the functionality on the printing device is not constrained.

Moreover, the invention allows matching, with high precision, paper transport timing with printing timing in the inkjet printing section, so that printing can be carried out without image shift.

Also, the cleaning operation of the inkjet heads can be performed in response to an instruction from the printing device, whereby the cleaning operation can be carried out in accordance with the number of print sheets, or during a temporary printing stop, during mass printing, while preventing function impairment on account of, for instance, clogging in the inkjet printing section.

An inkjet printer can also be easily constructed, with enhanced usability, when the paper feeding device is directly connected to the paper discharge device.

Moreover, printing can be diversified by storing print data in an internal memory and by reading the data upon printing.

Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without departing from the scope thereof. 

1. An option-type paper feeding device, comprising: a paper stacking section; a paper feeding mechanism for separating and feeding, sheet by sheet, paper from the paper stacking section; an intermediate transport section, arbitrarily connectable to a paper feeding section of a printing apparatus for printing in use of a plate, for transporting the paper fed by said paper feeding mechanism towards the paper feeding section of said printing apparatus; and an inkjet printing section provided in the intermediate transport section, wherein said intermediate transport section comprises first paper transport means provided facing said inkjet printing section, and second paper transport means provided downstream in a transport direction of the first paper transport means, and a transport speed of said first paper transport means is fixed to a substantially constant speed, and a transport speed of said second paper transport means is variable.
 2. The option-type paper feeding device according to claim 1, further comprising control means for, on the basis of printing speed information from said printing apparatus, adjusting the transport speed of said second paper transport means so as to match said printing speed, when said option-type paper feeding device is communicably connected to said printing apparatus.
 3. The option-type paper feeding device according to claim 1, wherein said paper stacking section is capable of stacking thereon a larger amount of paper than the paper feeding section of said printing apparatus.
 4. The option-type paper feeding device according to claim 1, wherein at least said first paper transport means, among said first paper transport means and said second paper transport means, has a structure in which paper is suctioned and thereby transported by electrostatic forces or by air negative pressure.
 5. The option-type paper feeding device according to claim 1, wherein the option-type paper feeding device can be used as an inkjet printer by being directly connectable to a paper discharge device, without said printing apparatus being interposed therebetween.
 6. The option-type paper feeding device according to claim 5, wherein printing by said inkjet printing section can be stopped on the basis of information from said paper discharge device, when said option-type paper feeding device is communicably connected to said paper discharge device.
 7. The option-type paper feeding device according to claim 5, further comprising control means for temporarily storing print data in a memory, and for enabling supplementary printing by said inkjet printing section through reading of the stored data.
 8. The option-type paper feeding device according to claim 1, further comprising cleaning means for cleaning an ink head of said inkjet printing section, said cleaning means being operated on the basis of a cleaning signal.
 9. The option-type paper feeding device according to claim 1, further comprising a press roller abutting an end of said first paper transport means on an upstream side of the transport direction, for pressing the paper. 